Exhaust gas muffler



May 26, 1970 w. F. MALKlE-:wlcz

EXHAUST GAS MUFFLER 2 Sheets-Sheet l gmx Filed Deo. 6, 1967 www May 26, 1970 w. F. MALKlEwlcz 3,513,939

EXHAUST GAS MUFFLER Filed De 6, 1967 2 Sheets-Sheet 2 INVENTOR. l

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United States Patent O 3,513,939 EXHAUST GAS MUFFLER Wladyslaw F. Malkiewicz, Jackson, Mich., assignor to Walker Manufacturing Company, Racine, Wis., a corporation of Delaware Filed Dec. 6, 1967, Ser. No. 688,495 Int. Cl. F01n 1/02 U.S. Cl. 181-54 6 Claims ABSTRACT OF THE DISCLOSURE An automotive exhaust rnuifller of the tri-flow type |has a pair of longitudinally extending partitions of triangular configuration mounted in an outer shell and secured by mechanical tab connections to transverse partitions so as to minimize spot-welding in a number of diiferent parts inside the muflier.

BACKGROUND OF THE INVENTION In the highly competitive mass manufacture of exhaust mufliers for automobiles and trucks there is continuous pressure for engineering `advances to provide better utilization of the steel used iu the manufacture of the muffler, reduction of manufacturing costs, reduction of handling costs in the manufacturing process, and reduction in the need for specialized equipment to manufacture the muflier. At the same time that advances are made in these directions the acoustical properties of the muilier must not be sacrificed and if possible must be improved.

=It has been substantially universal in commercial practice to form the internal constnuc'u'on of an automotive type mufiier out of tubular parts, such as gas flow tubes, spit chambers, tuning shells, etc. Generally, these tubular parts contain louvers or apertures of a given individual size in total area. Since it is relatively diicult to form apertures in a tube, necessitating, at the least, some specialized equipment, it has been general practice to form the apertures in flat strips of metal and then roll these into the tubular element.

BRIEF SUMMARY OF THE INVENTION It is a general purpose of the present invention to minimize the use of tubular elements in the internal construction of the muffler and also to minimize the use of spot-welding by means of mechanical tab connections between certain of the parts. The internal construction provided by this invention centers around the use of longitudinally extending partitions which are bent from originally flat metal after formation of apertures in such away that when disposed inside of the muffler shell they provide the gas passages and chambers normally provided by tubular elements. The longitudinal partitions are prefenably furnished with tabs that fit into openings in transverse partition so as to properly secure the various partitions to one another.

DESCRIPTION OF THE DRAWINGS FIG. l is a longitudinal cross section through a muflier embodying the invention;

FIG. 2. is an end elevation taken from FIG. l;

iFIG. 3 is a plan view of the transverse partition at the inlet end of the muffler;

FIG. 4 is a section along the line `4 4 of FIG. 3;

FIG. 5 is a plan view of the transverse partition at the outlet side of the muflier;

FIG. 6 is a cross section along the line 6-6 of FIG. 5;

FIG. 7 is a plan view of the blank from which the longitudinal partitions are formed;

FIG. 8 is Ian enlarged section along the line 8-8 of FIG. 5;

FIG. 9 is an end view of the tap construction that fits in the embossment of FIG. 8;

FIG. 10 is a side elevation of the tab structure of FIG. 9;

FIG. 1l is an enlarged cross section along the line 11 of FIG. 7; and,

FIG. l2 is a side elevation partly in section of a typical louver that may be formed in the longitudinal partitions.

DESCRIPTION OF THE INVENTION The muiiler 1 has an outer shell 3 which is preferably oval in cross section and has one end closed by a transverse inlet header 5 and the other end closed by a transverse outlet header 7, the headers being interlocked with the ends of a shell 3 by means of gas-tight rolled joints 9. The interior of the shell 3 is divided into three longitudinally separated chambers 11, 13, and 15 by means of transverse partitions 17 and 19 which have peripheral flanges Z1 and 23 respectively, that iit around the interior of the shell and are spot-welded to it `as indicated by the xs in the drawings. An inlet bushing 25 for attachment to the exhaust pipe of an internal combustion engine is mounted in the neck 27 formed in the inlet header 5 and in a neck 29 formed in the partition 17, preferably being spot-welded to both. The inlet bushing 25 extends through the chamber 11, and being imperforate and out of direct gas iiow communication with the chamber.

An outlet tube 31, for attachment to a tail pipe of an internal combustion engine system, is mounted in a neck 33 of the outlet header 7 and in a nec-k 35 of the partition 19, being spotJwelded preferably to both necks. The tube 31 is preferably imperforate in that portion extending through the chamber 15.

A tuning tube 37 is spot-welded in a neck 39 in the partition 19 and extends into the chamber 15 and provides the only inlet and outlet for the chamber to provide a Helmholtz type resonator for silencing a predetermined frequency.

Located in chamber 13 and extending between and connected to the partitions 17 and 19 are two longitudinally extending partitions 41 and 43 which may be formed from a blank 45 of the type illustrated in FIG. 7. The blank 45 is bent along lines 47 and 49 .to form flanges 51 which may be spot-welded to the shell 3 slightly over center as seen in FIG. 2. The blank 45 is also bent along lines 53, 55, 57, and 59 to'form a shell contacting central section 61. It is also bent along the lines 63 and 65 to form the flanges 67 which engage the shell directly opposite to the section 61 and which may be spot-welded or stapled to the shell. Extending between the ange 51 and the shell contacting portion 61 is a flat section 69 and extending between the flange 67 and the shell contacting portion 61 is a fiat section 71 on each of the partitions. Three sections 73, 75, and 77 of portion 69 which extend between the iiange 51 and the portion 61 are deformed outwardly from the plane of the sheet to a contour that substantially fits the inside of the shell 3 and thus comprise partition supporting ribs or embossments. These are preferably spot-welded to the shell.

The longitudinal partition 43 will be formed by the blank illustrated in FIG. 7 and it Will be seen that the section 71 is provided with a hole pattern 79 comprising nine holes of three different diameters and these may be formed with a slight lip 81 extending in the direction of flow as seen in FIG. 11. Also formed on the Section 71 of the partition 43 is a rectangular patch 83 of louvers with a shape known in the art which preferably extend inwardly toward the center of the shell 3. The hole pattern 79 and the louver patch 83 are omitted in the section 71 of the partition 41.

With the `structure so far described it will be seen that gas entering the inlet bushing can liow into a longitudinal passage 87 which is defined by the sections 71 and 69 of the partition 43. Slugs of gas can pass through the tuning tube 35 into the dead end or resonator chamber 15. Gas leaving the passage 87 will flow for the most part through the holes of hole pattern 79, although cross-bleeding can occur through the louvers in patch 83, into an intermediate passage 89 which is defined by the two facing sides 71 of the two partitions 41 and 43. The gas in passage 89 is flowing in a reverse direction toward the front of the muf'lier and liows through a hole pattern 97 comprising nine holes of different diameters as seen in FIG. 4 into the cross-over chamber 11. From chamber 11 the gas fiows through a pair of holes 93 and a large necked hole 95 into a passage 97 defined by the fiat sections 71 and 69 of the partition 41. The gas in the passage 97 then flows out of the muffler through the outlet tube 31.

The ribs or embossments 73, 75, and 77 subdivide the subchamber 99 between the partition 41 and the shell and the subchamber 101 between the partition 43 and the shell into two small volume chambers 99a and 99b which may, as illustrated in FIG. l, be of slightly different lengths. A louver patch 103 is formed in the section 69 of each partition to open into the chamber 99a and 101:1 and the louver patch 105 is also formed in the section 69 to open into the chamber 99b and 10119. These louvers and chambers therefore constitute small volume high frequency sound attenuating spit chambers for removing scratch and high frequency roughness.

Because of the variation in pressure or pulsation of gas going through the muffler it is desirable to attach the longitudinal partition to the transverse partition. This is accomplished by a mechanical connection comprising tab elements 107 which are formed from fiat stock and have fiat attachment sections 109 that are spot-welded to the section 71 of each partition 41 and 43 at the four locations indicated in FIG. 7. The tabs 107 have a neck 111 which projects beyond the edge of the partition and which connects a circular head section 113 of a split sleeve configuration as seen in FIG. 9 to the base 109. The heads 113 of the tabs are in alignment with embossments 11S in the partitions 17 and 19 and project through the apertures 117 in the embossnients. The embossments 115 are shaped as indicated and project outwardly of their respective partitions, that is, toward the adjacent end of the muffler. The length of the neck 111 on each tab is such that the head 113 can pass completely through the aperture 117 whereupon a suitable tool can be inserted in a slot 119 in the head to open is up or expand it so that it will lock against the surface of the embossrnent 115 and prevent the transverse and longitudinal partitions from separating.

In operation, gas entering the muflier 1 through the inlet bushing 25 fiows into the passage 87 and has acoustic communication through the louver patches 103 and 105 with the chambers 101e and 1011: for attenuation of high frequency sounds. Acoustic communication through the tuning tube 37 with the chamber 15 provides a resonator or Helmholtz action which may be tuned to silence a desired frequency of sound and is adapted to attenuating a relatively low frequency. Gas Hows through the hole pattern 79 into the reverse fiow passage 89 and to some extent to the louver patch 83 into the passage 89. The louver patch 83 and the volume of passage 89 provide an acoustic action that attenuates intermediate ranges of frequencies. The gas in passage 89 passes-through the hole pattern 91 into the chamber 11 and then back through holes 93 and 9S into the passage 97 and then into the outlet tube 31. Gas in the passage 97 has acoustic communication with the chambers 99a and 9911 through the louver patches 103 and 105 in the partition 41 and these also act to attenuate high frequency noises and roughness. The varying sizes of holes patterns 91 and 79 as 4 well as holes 93 and 95 along with the lips o1' necks provided around these holes also serve to remove sound energy from the gas as it passes through the mufiier.

Modification may be made in the structure of this invention without departing from the spirit or scope of the invention.

What is claimed is:

1. `ln an exhaust mulier for internal combustion engines, a. tubular shell closed at opposite ends and having an inlet at one end and an outlet at the other end, internal gas passage structure in the shell connecting the inlet and outlet and including a pair of longitudinally separated transverse partitions secured to the shell and defining a space between them, longitudinal partition means in said space subdividing it into longitudinally extending transversely separated chambers, apertures in said transverse and longitudinal partition providing means interconnecting said longitudinal chambers to provide for gas flow through said chambers between the inlet and the outlet, said longitudinal partition means having longitudinally extending split sleeve tabs extending through embossed holes in the transverse partitions to mechanically connect the longitudinally partition means to the transverse partitions.

2. in an exhaust mufiier for internal combustion engines, a tubular shell closed at opposite ends and having an inlet at one end and an outlet at the other end, internal gas passage structure in the shell connecting the inlet and outlet and including 4a lpair of longitudinally separated transverse partitions secured to the shell and defining a space between them, longitudinal partition means in said space and subdividing it into longitudinally extending transversely separated chambers, apertures in said transverse and longitudinal partition providing means interconnecting said longitudinal chambers to provide for gas flow through said chambers between the inlet and the outlet, said longitudinal partition means comprising a sheet metal part of triangular cross sectional configuration in contact at three points with the shell.

3. A mufiier as set forth in claim 2 including a second triangularly shaped sheet metal part transversely spaced from the first metal part, the spaces inside each part and the space between them each providing a chamber for gas fiow.

4. A mufiier as set forth in claim 3 including ribs formed in a part and engaging the shell to form a chamber.

5. In an exhaust muffler for internal combustion engines, a tubular shell closed at opposite ends and having an inlet at one end and an outlet at the other end, internal gas passage structure in the shell connecting the inlet and outlet and including a pair of longitudinally separated transverse partitions secured to the shell and defining a space between them, a pair of longitudinal extending partition means in said space each including a pair of longitudinal walls subdividing the space into ve longitudinally extending transversely separated chambers, said chambers being empty and the pair of walls acting with each other and with the shell to define said chambers, apertures in said transverse partitions and in said longitudinal walls interconnecting three of said longitudinal chambers, the entire widths of said three chambers serving as gas flow passages to provide for gas fiow through said shell between the inlet and the outlet, the remaining two chambers communieating with said three chambers and serving as sound attenuating chambers.

6. In a muffler for internal combustion engines, a tubular shell closed at opposite ends and having an inlet at one end and an outlet at the other end, internal gas passage and silencing structure in the shell connecting the inlet and outlet and including intersecting members, one of said members having an embossed hole means and the other having a projecting split sleeve tab extending through and locked behind the hole means to mechanically connect the intersecting members together.

(References on following page) References Cited UNITED STATES PATENTS 6 FOREIGN PATENTS 1,060,334 11/1953 France.

roigtlt et al' ROBERT S. WARD, IR., Primary Examiner Deremer 181-54 5 l -Nordquest et al. 181-54 XR U'S' C1 XR' JCIIghOI 181 54 181-61 

